Remote Focusing Devices

Voice coils, also known as linear actuators, play a crucial role in implementing aberration-free remote focusing in navigate. These electromagnetic actuators are used to control the axial position of the light-sheet and the sample relative to the microscope objective lens. By precisely adjusting the axial position, the focal plane can be shifted without moving the objective lens, thus enabling remote focusing.

Focus tunable lenses serve as an alternative to voice coils owing to their simple operation and high bandwidth. Tunable lenses axially scan a beam by introducing defocus into the optical train. Nonetheless, they do not provide the higher-order correction provided by voice coils in an aberration-free remote focusing system.

Equipment Solutions

LFA-2010

Configuration of the device can be variable. Many voice coils we have received require establishing serial communication with the device to explicitly place it in an analog control mode. In this case, the comport must be specified properly in the configuration file.

More recently, Equipment Solutions has begun delivering devices that automatically initialize in an analog control mode, and thus no longer need the serial communication to be established. For these devices, we recommend using the analog control mode described in the next section.

The LFA-2010 Linear Focus Actuator is controlled with a SCA814 Linear Servo Controller, which accepts a +/- 2.5 Volt analog signal. The minimum and maximum voltages can be set in the configuration file to prevent the device from receiving a voltage outside of its operating range.

Configuration File

microscopes:
  microscope_name:
      remote_focus_device:
        hardware:
          type: EquipmentSolutions
          channel: PXI6269/ao3
          min: -5.0
          max: 5.0
          port: COM2
          baudrate: 9600

Analog Controlled Voice Coils and Tunable Lenses

In principle, this hardware type can support any analog-controlled voice coil or tunable lens. The BLINK and the Optotune Focus Tunable Lens are controlled with an analog signal from the DAQ.

Thorlabs BLINK

The BLINK is a voice coil that is pneumatically actuated voice coil. It is recommended that you specify the min and max voltages that are compatible with your device to prevent the device from receiving a voltage outside of its operating range.

Configuration File

microscopes:
  microscope_name:
      remote_focus_device:
        hardware:
          type: NI
          channel: PXI6269/ao3
          min: -5.0
          max: 5.0
          port: COM2
          baudrate: 9600

Optotune Focus Tunable Lens

Configuration File

microscopes:
  microscope_name:
      remote_focus_device:
        hardware:
          type: NI
          channel: PXI6269/ao3
          min: -5.0
          max: 5.0
          port: COM2
          baudrate: 9600

Synthetic Remote Focus Device

If no remote focus device is present, one must configure the software to use a synthetic remote focus device.

Configuration File

microscopes:
  microscope_name:
    remote_focus_device:
        hardware:
          type: synthetic
          channel: PXI6269/ao3
          min: -5.0
          max: 5.0
          port: COM2
          baudrate: 9600